Electric plug



M. A. ROLLMAN ELECTRIC PLUG Dec. 4, 1934.

Filed July 17, 1933 Patented Dec. 4, 1934 ELECTRIC PLUG Michael A. Rollman, Mount Joy, Pa.

Application July 17, 1933, Serial No. 680,844

Claims.

The object of this invention is to so construct a plug that it will not only be easy to manufacture and assemble but will also be of such sturdy structure that it will be less liable to 5 fracture and short-circuit in use and will therefore be more acceptable to the fire underwriters, as more fully hereinafter set forth.

Referring to the drawing annexed, Fig. 1 is a perspective view showing the two main parts of the plug separated.

Fig. 21s a vertical sectional view taken through the assembled plug. Fig. 3 is a vertical sectional view taken at right angles to the line on which Fig. 2 is taken. Fig. 4 is a bottom view of the plug.

Fig. 5 is an exploded perspective showing a modified form of my device. i

,Referring to the drawing annexed by reference characters, 10 designates the usual twowire cord connected to the plug extending down through the top of the plug and connected respectively to the contact screws 11 of the usual pin clamps 12 housed in the body of the plug. The upper part of the plug consists of a cap 13 of insulating material, in which is imbedded ferrule 14 having attached to it a length of cord armor 15. The double cord 10 extends downwardly through the armor 15 in the ferrule 14, into a central cavity 16 formed in the cap, this 0 cavity extending entirely through the cap.

The cap-13 fits down upon a unitary body 17 which houses the aforesaid pin'clamps. 12, and the body and the cap are detachably fastened together by means of screws 18 extending through holes in upwardly projecting ears 19 formed on the side edges of the body 1'1. These ears 19 fit into cavities 20 at the opposite ends of the cap 13, so that when the screws 18 are threaded into the body of the cap 13 the two members, 13 ,and 17, will be solidly but detachably connected together. To give rigidity to the structure the cars 19 are made to exactly fit the cavities 20, and the lower side edges 21 of the cap fit down solidly on the top edges of the body 1'7.

The body 1'7 is cast or moulded in a single piece, its interior being divided centrally by means of a heavy partition member 22, this partition 22 together with the edge walls of the body 17 forming the cavities for the reception of the pin-clamps 12. In assembling the device, I first thread the cap 13 onto the end of the cord,

. then clamp the respective wires under the clamp screws 11, and then drop the pin-clamps 12 down into their respective cavities. These pin-clamps do not have to be fastened in place by means of screws as they are held in place at their upper ends by the bottom wall of the cap 13 and at. their lower ends by inwardly projecting lugs 23 formed near the lower ends of the pin-clamp cavities. The upper edge of the integral partition 22 projects above the side edges of the body part 17 so as to thereby serve to spread the terminals of the two cord members and thus insure against short-circuiting at that point.

It will be observed that my device consists practically of two main parts, each of which may be easily moulded, and that further the assembly of the device is rendered a very simple operation. The feature of most importance, however, is that this construction enables me to provide a very durable, sturdy casing for the exposed parts of the electric members and that therefore the chance of fracturing the body member by rough handling thereof is'rendered extremely unlikely. The sturdy housing, with its substantial division wall 22 renders shortcircuiting unlikely. It will be observed therefore that I have designed a plug which reduces replacements to a minimum and also fire risk to a minimum. For the purpose of preventing the pin-clamps 12 from shifting about after they are properly set and housed, a pair of notches 24 is provided in the underside of the cap 13 v for the reception of the upper ends of these pin-clamps. These notches, together, with the lugs 23 at the bottom hold the clamps always in proper position and without lateral or endwise body movement within their respective cavities.

It will be observed that the cars 19 are made integral with the body 17-and that they are the full width of the edge walls of the body thereby giving me an unusually sturdy structure that may be handled with little fear of breakage. 95 By having theattaching ears 19 on the. edge. walls rather than on the side walls of the body I am enabled to make the cavities 20 deep enough to receive the heavy thick ears 19, which would not be the case if the ears and cavities were placed onthe side walls of the device, since deep cavities and thick ears on the side walls would weaken the cap too much. It is essential that the ears 19 shall be thick in order that they may not readily break off. These heavy integral ears fitting into deep cavities in the ends of the cap together with the abutting of the lower edges 21 of the cap against the top edges of the side walls of the body, as shown particularly in Fig. 3, provides a solid, socket-like joint between the cap and the body and thus enables the parts to be fastened rigidly together without threading one into the other, threading one into the other being objectionable because such connection is too frangible for a device of this character.

In Fig. 5 I show a slight modification in which the cap 13 is divided in half vertically and longitudinally, with one half, namely, 13'- moulded integrally with the body member 17 while the other'half 13 is moulded separately and adapted to be detachably fastened in position by screws, not shown. The screws pass freely through unthreaded holes 25 in the removable cap tapped into threaded holes 26 in the other half of the cap. The manner of assembling and disassembling is substantially the same as with the other form of the device herein described.

I claim: a

1. In a device of the character described, a hollow body member having a vertical division wall extending from side to side and a pair of ears projecting upwardly from its edge walls, all said parts being formed integral of an insulating material, a cap or top member formed integral of an insulating material, and having a central passage for the wire cords and cavities in its end walls adapted to receive and fit the aforesaid upstanding ears, the bottom edges of the side walls of the cap abutting the top edges of the side walls of the body, and fastening devices extending through said ears and into the body of the cap.

2. The structure recited in claim 1, the bottom face of the cap being provided with notches adapted to fit down over the usual pin-clamps mounted in the passages formed by the division wall.

3.' The structure recited in claim 1, the passages .formed by the division wall in the body being provided at their bottoms with upstanding bevelled lugs adapted to fit between the two lower ends of the usual pin-clamps enclosed in the passages to thus prevent the pin-clamps from rattling in the passages.

4. The structure recited in claim 1, the bottom wall of the cap being provided with downwardly facing notches adapted to receive the upper ends of the usual pin-clamps, and the passages formed in the body by means of the division wall being provided at their bottoms with upstanding lugs adapted to fit between the two members of the usual pin-clamps.

5. The structure recited in claim 1, said division wall in the body being extended a distance up into the passage through the cap to thereby separate the usual pair of cord wires running down through said passage.

MICHAEL A. ROLLMAN. 

